JP2018172603A - Resin composition, method for manufacturing the same, pre-preg, and molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition capable of suppressing core-shell particles from being localized when impregnating into a reinforced fiber base material, a method for manufacturing the same, a pre-preg, and a molding excellent in 90° bending.SOLUTION: A resin composition (R) includes an epoxy resin (A), a curing agent (B), and vinyl polymer particles (C). The vinyl polymer particles (C) are core-shell particles having a core layer comprising an acryl resin and a shell layer. The content of the vinyl polymer particles (C) in the resin composition (R) is 2 pts.mass or more and 30 pts.mass or less based on 100 pts.mass of the epoxy resin (A). The average particle diameter of the primary particle of the vinyl polymer particle (C) is 0.5 μm or more and 1.0 μm or less, the viscosity of the resin composition (R) at 30°C is (3.0×10) Pa s or more and (5.0×10) Pa s or less, and the maximum particle diameter of the secondary particle of the vinyl polymer particle (C) in the resin composition (R) is 3 μm or less.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition and a method for producing the same, a prepreg, and a molded body.

  A fiber reinforced composite material composed of reinforced fibers and a matrix resin is lightweight and has excellent mechanical properties. Therefore, it is widely used in sports equipment such as structural materials such as aircraft, vehicles, ships and buildings, golf shafts, fishing rods and tennis rackets.

  Various methods are used for manufacturing the fiber-reinforced composite material. Among them, a method using a prepreg which is a sheet-like, tape-like, or string-like intermediate substrate in which a reinforcing fiber substrate is impregnated with a matrix resin composition is widely used. In this method, a plurality of prepregs are laminated and then heated and cured to obtain a fiber-reinforced composite material (hereinafter sometimes referred to as “molded body”).

  As the matrix resin composition used for the prepreg, a thermosetting resin or a thermoplastic resin is used. In many cases, a thermosetting resin composition is used.

  When manufacturing a fiber reinforced composite material using a prepreg, the “resin flow amount” is often a problem. That is, when the viscosity of the matrix resin composition is lowered in order to sufficiently impregnate the matrix resin composition into a reinforcing fiber substrate (hereinafter sometimes simply referred to as “substrate”), the obtained prepreg is molded. In the heating / pressurizing step, the matrix resin composition may flow out excessively, resulting in poor appearance of the resulting molded product. In addition, the reinforcing fiber may meander to adversely affect physical properties. On the other hand, when the viscosity of the matrix resin composition is increased in order to appropriately control the resin flow amount, the impregnation property to the base material and the drape property of the obtained prepreg tend to be lowered.

  In order to solve such a problem, Patent Document 1 proposes a resin composition including a matrix resin, a curing agent, and core-shell particles in which both the core layer and the shell layer are made of an acrylic resin. According to the technique described in Patent Document 1, all of the good impregnation property of the matrix resin composition to the reinforcing fiber substrate, the high drapability of the resulting prepreg, and the appropriate flow amount at the time of molding are obtained. The

International Publication No. 2016/060166

  However, since the core-shell particles contained in the matrix resin composition of the resin composition described in Patent Document 1 are aggregated, the aggregated core-shell particles are reinforced fiber when impregnating the reinforcing fiber substrate with the resin composition. Filtered to the substrate and localized on the surface. For this reason, when a prepreg is prepared by impregnating the resin composition of Patent Document 1 into a reinforcing fiber base, and a molded body is produced using this prepreg, stress is applied to the interface of localized core-shell particles. Concentration causes a problem that the mechanical properties are degraded. In particular, in a bending test performed in a direction orthogonal to the fibers of the molded body (90 ° direction), the resin mainly bears the load. ° There was a problem that the bending strength was likely to decrease.

  The present invention has been made in view of the above problems, and a resin composition capable of suppressing the localization of core-shell particles when impregnated into a reinforcing fiber base, a method for producing the same, and the resin composition An object of the present invention is to provide a prepreg obtained by impregnating a reinforced fiber base material and a molded body produced by the prepreg.

As a result of intensive studies by the present inventors to solve the above problems, in the resin composition, the secondary particles of the core-shell particles are crushed and the particle size of the secondary particles is reduced as much as possible. It has been found that by realizing a state in which the secondary particles are not substantially contained, it is possible to suppress the occurrence of localization when impregnating the reinforcing fiber base as described above. And it discovered that the molded object excellent in 90 degree bending strength was obtained by manufacturing a molded object from the prepreg obtained using this resin composition, and came to complete the following invention.
That is, this invention has the following aspects.
[1] A resin composition (R) containing an epoxy resin (A), a curing agent (B), and vinyl polymer particles (C), wherein the vinyl polymer particles (C) are made of an acrylic resin. Core-shell particles having a core layer and a shell layer, wherein the content of the vinyl polymer particles (C) in the resin composition (R) is 2 parts by mass with respect to 100 parts by mass of the epoxy resin (A). It is 30 parts by mass or less, the average particle diameter of primary particles of the vinyl polymer particles (C) is 0.5 μm or more and 1.0 μm or less, and the viscosity of the resin composition (R) at 30 ° C. is 3 0.0 × 10 ¹ Pa · s to 5.0 × 10 ³ Pa · s, and the maximum particle size of secondary particles of the vinyl polymer particles (C) in the resin composition (R) is 3 μm or less. The resin composition (R).
[2] The glass transition temperature of the shell layer in the vinyl polymer particles (C) is 85 ° C. or higher and 115 ° C. or lower, and the solubility parameter of the shell layer is 20.00 [(J / cm ³ ) ^1/2 ] 21.50 [(J / cm ³ ) ^1/2 ] or less, and the mass ratio of the shell layer to the core layer (shell layer: core layer) is 50:50 to 10:90 The resin composition (R) according to [1].
[3] The vinyl polymer particle (C) prepares an emulsion containing a vinyl polymer by emulsion polymerization of at least two kinds of vinyl monomer mixtures having different compositions in two or more stages. The resin composition (R) according to the above [1] or [2], which is particles obtained by spray-drying an emulsion containing the resin.
[4] At least one vinyl monomer mixture having at least two different compositions is selected from the group consisting of (meth) acrylate and (meth) acrylic acid that can have a functional group. Resin composition (R) as described in any one of said [1]-[3] which is a mixture containing a vinyl monomer.
[5] A method for producing the resin composition (R) according to any one of [1] to [4] above, wherein the viscosity at 30 ° C. is 1.0 × 10 ² Pa · s or more. A portion of the epoxy resin (A) that is less than or equal to 0 × 10 ⁴ Pa · s is taken, and a core layer made of an acrylic resin and vinyl polymer particles (C) that are core-shell particles having a shell layer are mixed therewith. Step (I) to obtain a mixture (X), step (II) for crushing secondary particles of the vinyl polymer particles (C) contained in the mixture (X), and the mixture (X) A process for producing the resin composition (R), comprising: the remainder of the epoxy resin (A) and the step (III) of adding and mixing the curing agent (B).
[6] A prepreg comprising the resin composition (R) according to any one of [1] to [4] above and a reinforcing fiber substrate.
[7] A molded product obtained by curing the prepreg according to [6] by heating and pressing.

According to the resin composition and the method for producing the same of the present invention, the prepreg is impregnated into the reinforcing fiber base material by making the secondary particles of the vinyl polymer particles (C) composed of the core-shell particles substantially free. The impregnation property at the time of producing is improved, and the occurrence of localization of secondary particles can be suppressed.
Moreover, according to the prepreg of the present invention, since the reinforcing fiber base material is impregnated with the resin composition of the present invention, localization of secondary particles having a relatively large diameter is suppressed.
And according to the molded object of this invention, since it was obtained from the prepreg manufactured from the resin composition of this invention, it will have the outstanding 90 degree bending strength.

  Hereinafter, the resin composition of the present invention, the production method thereof, the prepreg, and the molded body will be described in detail.

  The term “epoxy resin” is generally used as the name of one category of a thermosetting resin or the name of a category of a chemical substance called a compound having an epoxy group in the molecule. Is used to mean Moreover, the composition of an epoxy resin means that it is a composition containing an epoxy resin, a hardening | curing agent, and the other additive by the case.

In the present invention, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acrylic acid” is the same.
Further, in the present invention, the “acrylic resin” means a polymer formed by polymerizing a monomer selected from the group consisting of (meth) acrylate and (meth) acrylic acid that can have a functional group as described later. Means coalescence.

<Resin composition (R)>
The resin composition (R) of the present invention contains an epoxy resin (A), a curing agent (B), and vinyl polymer particles (C).

[Epoxy resin (A)]
The epoxy resin (A) in the present invention is not particularly limited as long as it has the effects of the present invention. Examples include glycidyl ether type, glycidyl amine type, glycidyl ester type, and alicyclic epoxy type. Among these, it is preferable to include a glycidyl ether type or a glycidyl amine type from the viewpoints of being inexpensive, easily available, having good water resistance, and high reactivity.

  As the glycidyl ether type or glycidyl amine type, it is preferable that at least two glycidyl groups are contained in one molecule from the viewpoint of heat resistance. Specific examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, and triphenylmethane type epoxy resin. Among these, the epoxy resin (A) includes a bisphenol A type epoxy resin from the viewpoint of heat resistance and toughness of a cured product of the epoxy resin (A) (hereinafter sometimes referred to as “resin cured product”). Is preferred.

  Moreover, an epoxy resin (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

  In addition, as an epoxy equivalent (g / eq.) Of an epoxy resin (A), 100-500 are preferable and 150-400 are more preferable. When the epoxy equivalent of the epoxy resin (A) is within the above range, a cured product having high heat resistance is easily obtained without impairing curability.

  In addition, as the mass average molecular weight of the epoxy resin (A), the vinyl polymer particles (C) described later can be easily dissolved or swollen in the resin composition (R) of the present invention. Further, from the viewpoint of easier adjustment of the viscosity of the resin composition (R), it is preferable to contain a relatively large amount of a low molecular weight.

Specifically, the epoxy resin (a1) having a mass average molecular weight of 100 to 480 is preferably contained in an amount of 30 parts by weight or more and 90 parts by weight or less with respect to 100 parts by weight of the epoxy resin (A). More preferably, the content is at least 80 parts by weight.
By setting the content of the epoxy resin (a1) to 30 parts by weight or more with respect to 100 parts by mass of the epoxy resin (A), it becomes easy to obtain a prepreg having a good drapability. Moreover, it becomes easy to control the resin flow amount at the time of press-molding the prepreg containing the resin composition (R) within an appropriate range. Furthermore, it is easy to impregnate the reinforcing fiber substrate with the resin composition (R) of the present invention at the time of preparing the prepreg. Moreover, by setting the content of the epoxy resin (a1) to 90 parts by weight or less with respect to 100 parts by mass of the epoxy resin (A), tackiness of the prepreg does not become too strong, and the shape of the prepreg can be easily maintained. .

Moreover, if the mass average molecular weight of an epoxy resin (a1) is 100 or more, resin itself will not volatilize easily and handling will become easier. Further, the viscosity does not become too low, and it becomes easier to maintain the shape of the prepreg when preparing the prepreg.
Moreover, if the mass average molecular weight of an epoxy resin (a1) is 480 or less, it will be easy to dissolve or swell vinyl polymer particle (C) easily, and the flow inhibitory effect at the time of press molding will become more favorable.
The mass average molecular weight of the epoxy resin (a1) is more preferably 150 or more and 480 or less.

Such an epoxy resin (a1) may be a mixture of a plurality of epoxy resins or a commercially available product.
A commercially available epoxy resin product is a mixture of a plurality of epoxy resins having different degrees of polymerization. Therefore, “molecular weight” described in commercially available epoxy resin products is an average value of molecular weights of individual compounds contained in the mixture. On the other hand, the “mass average molecular weight” of the epoxy resin (a1) in the present invention is a value calculated by gel conversion using gel permeation chromatography (GPC). Therefore, when using the above-mentioned commercial item as an epoxy resin (a1), each compound contained in an epoxy resin product is fractionated and fractionated by GPC, and a mass average molecular weight is calculated by polystyrene conversion.

  The epoxy resin (A) may contain an epoxy resin other than the above-described epoxy resin (a1) as long as the effects of the present invention are not impaired. In that case, the content of the epoxy resin other than the epoxy resin (a1) (hereinafter sometimes referred to as “other epoxy resin”) is preferably 70 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A). 50-20 mass parts is more preferable. In the epoxy resin (A), if the content of the other epoxy resin is within the above range, the vinyl polymer particles (C) are easily dissolved or swelled in the resin composition (R) as described later. The effect that it is easy to do becomes easy to be acquired.

  As a mass average molecular weight of an epoxy resin (A), 150-1500 are preferable and 200-1200 are more preferable. When the mass average molecular weight of the epoxy resin (A) is within the above range, a cured product having high heat resistance is easily obtained. In addition, the said mass mean molecular weight is the value computed by the method similar to the above-mentioned epoxy resin (a1).

  As content of the epoxy resin (A) in a resin composition (R), 60-90 mass parts is preferable with respect to 100 mass parts of resin compositions (R), and 65-85 mass parts is more preferable. When the content of the epoxy resin (A) is within the above range, a cured product having high heat resistance is easily obtained, and a cured product having high mechanical properties is easily obtained.

In one embodiment of the present invention, the viscosity at 30 ° C. of the epoxy resin (A) is preferably 1.0 × 10 ² Pa · s or more and 1.0 × 10 ⁴ Pa · s, and 1.5 × More preferably, it is 10 ² Pa · s or more and 5.0 × 10 ³ Pa · s or less. If the viscosity at 30 ° C. of the epoxy resin (A) is within the above range, an effect of improving the impregnation property to the reinforcing fiber bundle is easily obtained.

[Curing agent (B)]
The curing agent (B) in the present invention is not particularly limited as long as it can cure the epoxy resin (A) as long as it has the effects of the present invention. For example, an amine type, an acid anhydride type (such as a carboxylic acid anhydride), a phenol type (such as a phenol novolac resin), a mercaptan type, a Lewis acid amine complex type, an onium salt type, and the like can be given. Among these, amine-type or Lewis acid amine complex-type curing agents are preferred from the viewpoint of good storage stability and excellent curability. One of these curing agents may be used alone, or two or more thereof may be used in combination.

  Examples of amine-type curing agents include aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines, imidazole derivatives, dicyandiamide, tetramethylguanidine, thiourea-added amines, and isomers or modified products thereof. Can be mentioned. Among these, dicyandiamide or imidazole derivatives are preferable. If it is dicyandiamide, it is easy to obtain a prepreg superior in storage stability. If it is an imidazole derivative, the heat resistance of a molded object will become more favorable.

  Examples of the Lewis acid amine complex type curing agent include a boron halide amine complex. Specifically, for example, boron trifluoride / piperidine complex, boron trifluoride / monoethylamine complex, boron trifluoride / amine complex such as boron trifluoride / triethanolamine complex, boron trichloride / octylamine complex, etc. And boron trichloride amine complex. Among these Lewis acid amine complex type curing agents, in particular, the solubility in the epoxy resin (A) is excellent, the pot life when the resin composition (R) is made, and the curability is excellent. Therefore, a boron trichloride amine complex is preferable.

From the viewpoint of further increasing the curing activity of the curing agent (B), the curing agent (B) may contain a curing aid. For example, when dicyandiamide is used as the curing agent (B), 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-chloro It is preferable to contain urea derivatives such as -4-methylphenyl) -1,1-dimethylurea and 2,4-bis (3,3-dimethylureido) toluene (TBDMU) as a curing aid. Among these, a combination of dicyandiamide and DCMU or TBDMU is particularly preferable.
When a hardening agent (B) contains a hardening adjuvant, 1-15 mass parts is preferable with respect to an epoxy resin (A), and 2-10 mass parts is more preferable. If content of hardening adjuvant is in the said range, it will be easy to acquire the effect that a cured | curing material does not impair a mechanical physical property, and can control reactivity.

  Moreover, 3-25 mass parts is preferable with respect to an epoxy resin (A), and, as for content of the hardening | curing agent (B) in a resin composition (R), 5-20 mass parts is more preferable. When the content of the curing aid is within the above range, it is easy to obtain the effect that the cured product exhibits high mechanical properties and high reactivity can be obtained.

[Vinyl polymer particles (C)]
The vinyl polymer particle (C) in the present invention means fine particles obtained by spray-drying an emulsion containing a vinyl polymer obtained by emulsion polymerization of a radically polymerizable vinyl monomer.

Examples of the radically polymerizable vinyl monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, t -Butyl (meth) acrylate, i-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate , Phenyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate , Tricyclo [5.2.1.0 ^2,6] decan-8-yl - methacrylate, dicyclopentadienyl (meth) acrylate of (meth) acrylate; styrene, alpha-methyl styrene, aromatic and vinyl toluene Group vinyl monomer; hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol Hydroxyl group-containing (meth) acrylates such as mono (meth) acrylate; glycidyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N-methyl-2,2,6,6-tetramethylpiperidyl (meth) Functional groups (other than hydroxyl groups) such as acrylate Organic (meth) acrylate; acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, isocrotonic acid, salicylic acid vinyloxyacetic acid, allyloxyacetic acid, 2- (meth) acryloylpropanoic acid, 3- (meth) acryloylbutane Carboxyl group-containing vinyl monomers such as acid and 4-vinylbenzoic acid; vinyl cyanide monomers such as (meth) acrylonitrile; (meth) acrylamide; monomethyl itaconate, monoethyl itaconate, monopropyl itaconate, mono Itaconic acid esters such as butyl itaconate, dimethyl itaconate, diethyl itaconate, dipropyl itaconate, dibutyl itaconate; monomethyl fumarate, monoethyl fumarate, monopropyl fumarate, monobutyl fumarate, dimethyl fumarate Fumaric acid esters such as thiolate, diethyl fumarate, dipropyl fumarate, dibutyl fumarate; monomethyl malate, monoethyl malate, monopropyl malate, monobutyl malate, dimethyl malate, diethyl malate, dipropyl And maleic esters such as malate and dibutyl malate; and other vinyl monomers such as vinyl pyridine, vinyl alcohol, vinyl imidazole, vinyl pyrrolidone, vinyl acetate, and 1-vinyl imidazole. These monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  Among these monomers, (meth) acrylate or (meth) acrylic acid having a functional group is preferable because radical polymerization is easier and emulsion polymerization is easier. Here, the “(meth) acrylate that can have a functional group” is a general term for the above-described (meth) acrylate, hydroxyl group-containing acrylate, and (meth) acrylate (other than hydroxyl group).

  The vinyl polymer particles (C) can be produced by adding a polymerization initiator, an emulsifier, a dispersion stabilizer, a chain transfer agent, and the like to the above-described vinyl monomer as necessary. In addition, a polymerization initiator, an emulsifier, a dispersion stabilizer, a chain transfer agent, etc. can be selected from well-known materials. As these materials, for example, materials described in International Publication No. 2010/090246 pamphlet and the like can be used.

  As the above-mentioned polymerization method, since it is easy to obtain true spherical particles and the particle morphology is easy to control, emulsion polymerization method, soap-free emulsion polymerization method, swelling polymerization method, miniemulsion polymerization method, dispersion polymerization method, and fine polymerization method. A suspension polymerization method is preferred. Among these, a soap-free emulsion polymerization method is more preferable because vinyl polymer particles having superior dispersibility can be obtained. Further, industrially highly practical methods for controlling the particle morphology of vinyl polymer particles include, for example, a method in which vinyl monomer mixtures having different compositions are successively dropped and polymerized in multiple stages. .

  That is, as the vinyl polymer particles (C), particles obtained by emulsion-polymerizing a mixture of at least two kinds of vinyl monomers having different compositions in two or more stages and spray-drying the obtained emulsion containing the vinyl polymer. (Hereinafter sometimes referred to as “multistage polymer particles”). In this case, the mixture of at least two kinds of vinyl monomers having different compositions is at least one vinyl monomer selected from the group consisting of (meth) acrylate and (meth) acrylic acid that can have a functional group. A mixture containing a monomer is preferable.

  The vinyl polymer particles (C) thus produced are preferably core-shell particles having a core layer and a shell layer. That is, as the vinyl polymer particles (C), both the core layer and the shell layer are preferably core-shell particles made of an acrylic resin. In addition, as a method for determining whether the vinyl polymer particle (C) has a core-shell structure, for example, (1) the particle diameter of the vinyl polymer particle sampled in the polymerization process is surely growing. (2) A method for confirming that the minimum film-forming temperature (MFT) of the vinyl polymer particles sampled in the polymerization process and the solubility in various solvents are simultaneously satisfied. Is mentioned. In addition, a method of confirming the presence or absence of a concentric structure by observing the cut surface of the vinyl polymer particles (C) with a transmission electron microscope (TEM), or the vinyl polymer particles (C) freeze-fractured Examples include a method of observing the cut surface with a scanning electron microscope (cryo SEM) and confirming the presence or absence of a concentric structure.

  In addition, when the vinyl polymer particles (C) contained in the resin composition (R) of the present invention are obtained as multistage polymer particles as described above, a mixture of at least two types of vinyl monomers having different compositions is obtained. It is difficult to specify in detail how and how it is polymerized. That is, in the resin composition (R) of the present invention, there are circumstances (impossible / unpractical circumstances) that cannot be directly specified by the structure or characteristics, or are not practical. .

  In the resin composition (R) of the present invention, the vinyl polymer particles (C) exist as particles at room temperature (10 ° C. or higher and 30 ° C. or lower), but at high temperatures (over 60 ° C.), the resin composition (R) ), Specifically, dissolved in the epoxy resin (A) or swollen by the epoxy resin (A).

  That is, since the vinyl polymer particles (C) are present in the form of particles in the resin composition (R) at room temperature, that is, at a relatively low temperature, the viscosity of the resin composition (R) containing the vinyl polymer particles (C) is kept relatively low. Be drunk. Therefore, the resin composition (R) of the present invention has a high impregnation property with respect to the reinforcing fiber substrate, and the obtained prepreg has a good drape property. On the other hand, since the vinyl polymer particles (C) are dissolved in the epoxy resin (A) in the resin composition (R) or swollen by the epoxy resin (A) under a high temperature condition, the resin composition ( When press molding is performed using a prepreg in which R) is used, the resin composition is such that the vinyl polymer particles (C) dissolve or swell faster than the reaction between the epoxy resin (A) and the curing agent (B). Product (R) thickens. As a result, it becomes easy to reduce the resin flow amount.

  The vinyl polymer particles (C) are dissolved in the epoxy resin (A) at the working temperature such as when preparing the resin composition (R) of the present invention or when producing the prepreg using the resin composition (R). Or it does not swell with the epoxy resin (A), and dissolves in the epoxy resin (A) faster than the reaction between the epoxy resin (A) and the curing agent (B) in the temperature rising process at the time of molding the prepreg, or What swells with an epoxy resin (A) is preferable.

Specifically, vinyl polymer particles (C) having a melting start temperature with respect to the epoxy resin (A) or a swelling start temperature with the epoxy resin (A) of 60 ° C. or higher and 140 ° C. or lower are preferable. Further, the dissolution start temperature or the swelling start temperature is more preferably 80 ° C. or higher and 120 ° C. or lower.
Furthermore, as the vinyl polymer particles (C), those having a thickening start temperature of 70 ° C. or higher and 90 ° C. or lower are preferable.

  The dissolution rate or swelling rate of the vinyl polymer particles (C) can be appropriately selected within a range where the resin flow amount is in an appropriate range and the appearance of the molded body is better.

By using the above-described multistage polymer particles or core-shell particles as the vinyl polymer particles (C), it becomes easier to satisfy the above-described conditions. In particular, as the above-mentioned “mixture of at least two kinds of vinyl monomers having different compositions”, at least one vinyl monomer selected from the group consisting of (meth) acrylate and (meth) acrylic acid that can have a functional group. Multi-stage polymer particles obtained using a mixture containing a monomer and core-shell particles in which both the core layer and the shell layer are acrylic resins are preferred.
In addition, multistage polymer particle or core-shell particle becomes easy to melt | dissolve or swell, so that the mass mean molecular weight of an epoxy resin (A) is small.

  In order to sufficiently exhibit the flow suppressing effect at the time of press molding of the prepreg of the present invention (prepreg obtained by impregnating the reinforcing fiber substrate with the resin composition (R) of the present invention) described later, an epoxy resin (A It is preferable that dissolution of the multistage polymer particles or core-shell particles in the epoxy resin (A) or swelling by the epoxy resin (A) occurs at a temperature lower than the curing reaction temperature of The ease of dissolution or swelling of these particles in the epoxy resin (A) depends on the outermost emulsion polymer layer of the multistage polymer particles (hereinafter also referred to as “(i) layer”) or the shell of the core-shell particles. Glass transition temperature of the resin constituting the layer (hereinafter sometimes referred to as “Tg”), solubility parameter (hereinafter sometimes referred to as “SP value”), or core layer and shell layer (or multiple stages) It is affected by the mass ratio of the outermost emulsion polymer layer of the polymer particles and the other emulsion polymer layer (hereinafter sometimes referred to as “(ii) layer”). The higher the Tg of the (i) layer or the shell layer, the more difficult it is to dissolve or swell in the epoxy resin (A). Moreover, since the SP value of the epoxy resin (A) is generally lower than the SP value of vinyl polymer particles made of acrylic resin, the higher the SP value of the (i) layer or the shell layer, the more the epoxy resin (A) has. Difficult to dissolve or swell. Furthermore, the mass ratio of the core layer to the shell layer is less likely to be dissolved or swelled in the epoxy resin (A) when the ratio of the shell layer is higher. Moreover, as for the mass ratio of the (i) layer and the (ii) layer, the higher the ratio of the (i) layer, the harder it is to dissolve or swell in the epoxy resin (A). In view of these, it is necessary to select vinyl polymer particles (C) that meet the desired molding temperature.

For example, when the prepreg obtained from the resin composition (R) of the present invention is press molded at 140 ° C., the Tg of the shell layer is 85 ° C. or higher and 115 ° C. or lower, and the SP value of the shell layer is 20.00 [(J / Cm ³ ) ^1/2 ] to 21.50 [(J / cm ³ ) ^1/2 ], and the mass ratio of the shell layer to the core layer (shell layer: core layer) is 50:50 to 10: The vinyl polymer particles (C) consisting of 90 core-shell particles may be selected. Moreover, the preferable range of the SP value of the shell layer is 20.10 [(J / cm ³ ) ^1/2 ] or more and 21.3 [(J / cm ³ ) ^1/2 ] or less, and a more preferable range is as follows. 20.20 [(J / cm ³ ) ^1/2 ] or more and 21.0 [(J / cm ³ ) ^1/2 ] or less.
Alternatively, the Tg of the (i) layer is 85 ° C. or higher and 115 ° C. or lower, and the solubility parameter (SP value) of the (i) layer is 20.00 [(J / cm ³ ) ^1/2 ] or higher and 21.50 [( J / cm ³ ) ^1/2 ] or less, and the mass ratio of (i) layer to (ii) layer ((i) layer: (ii) layer) is 50:50 to 10:90 Vinyl polymer particles (C) made of particles may be selected.

  Here, the SP value is obtained by substituting the SP value (SP (Ui)) of the monomer unit constituting the polymer into the following formula (1), as described in the pamphlet of International Publication No. 2013/077293. Can do. SP (Ui) is described in Polymer Engineering and Science, Vol. 14, 147 (1974).

  In the above formula (1), Mj represents the molar fraction of the monomer unit j component, and ΣMj = 1.

The average particle diameter of the primary particles of the vinyl polymer particles (C) of the present invention is 0.5 μm or more and 1.0 μm or less, more preferably 0.6 μm or more and 0.9 μm or less, and 0.6 μm or more and 0.001 or less. More preferably, it is 8 μm or less. Here, “average particle size” means volume average primary particle size as emulsion particle size by diluting an emulsion of vinyl polymer particles (C) with ion-exchanged water and using a laser diffraction scattering type particle size distribution measuring device. To do.
By setting the average particle diameter of the primary particles to 0.5 μm or more, the secondary agglomerated vinyl polymer particles (C) can be easily crushed and dispersed as primary particles in the resin composition (R). . Further, the surface area of the vinyl polymer particles (C) does not become too large and reaction delay or the like hardly occurs.
Moreover, by making the average particle diameter of the primary particles 1.0 μm or less, the reinforcing fiber base material is impregnated without being separated by the vinyl polymer particles (C) and can be localized on the base material surface. In addition, it is possible to prevent a decrease in mechanical properties of the obtained molded body. Thereby, the molded object obtained by shape | molding the prepreg in which the resin composition (R) of this invention was used becomes excellent in 90 degree bending strength.

The vinyl polymer particles (C) having an average primary particle diameter of 0.5 μm or more and 1.0 μm or less generally constitute secondary particles by secondary aggregation of the primary particles. Since the diameter of such secondary particles is approximately 30 μm to 100 μm, the secondary particles remain even when dispersed uniformly in the resin composition (R). Therefore, when the reinforcing fiber substrate is impregnated with the resin composition containing such secondary particles, the secondary particles are separated by filtration and localized on the substrate surface.
Therefore, in the present invention, such secondary particles are crushed to return to primary particles, or the maximum particle size of secondary particles is suppressed to 3 μm or less.

Here, when the vinyl polymer particles containing the secondary particles are pulverized alone, the particles are dispersed in the form of powder during pulverization, and the recovery rate is lowered. Therefore, it is preferable to crush the secondary particles after mixing the liquid material such as resin and the vinyl polymer particles (C). With this method, primary particles can be efficiently recovered.
As the resin mixed with the vinyl polymer particles (C), the above-described epoxy resin (A) is preferable. When vinyl polymer particles (C) and epoxy resin (A) are mixed for crushing treatment, 100 to 800 parts by mass of epoxy resin (A) with respect to 100 parts by mass of vinyl polymer particles (C). It is preferable to make it the mixture which added and mixed by.

  As a method for crushing the secondary particles of the vinyl polymer particles (C), it can be carried out by a known method, for example, a raking machine, an attritor, a planetary mixer, a dissolver, a triple roll, a kneader, a universal agitator, It can carry out using a homogenizer, a homodispenser, a ball mill, and a bead mill. Among these, it is preferable to apply a method of applying a high share because the secondary particles can be easily crushed. Examples of such a high share method include a three-roll mill, a planetary mixer, a kneader, and a homogenizer. Among these, the method using a three-roll mill is most preferable from the viewpoint that the apparatus is simple and mass productivity is easy. In the case of using a three-roll mill, it is preferable to perform the crushing process by changing the speed of the three rolls and taking a higher share.

When crushing secondary particles with a three-roll mill, from the viewpoint of more share, the viscosity at 30 ° C. of the epoxy resin (A) dispersed in the vinyl polymer particles (C) is 1.0 × as described above. It is preferably 10 ² Pa · s or more and 1.0 × 10 ⁴ Pa · s or less, more preferably 2.0 × 10 ² Pa · s or more and 5.0 × 10 ³ Pa · s, more preferably 3.0 × 10 10 More preferably, it is ² Pa · s or more and 3.0 × 10 ³ Pa · s. If the viscosity at 30 ° C. of the epoxy resin (A) is 1.0 × 10 ² Pa · s or more, the shear is strong and the secondary particles are easily crushed. If the viscosity of the epoxy resin (A) at 30 ° C. is 1.0 × 10 ⁴ Pa · s or less, the secondary particles are crushed without swelling of the vinyl polymer particles (C) due to shear heat. Can do.

  By crushing the secondary particles contained in the vinyl polymer particles (C) by the above-described method, the resin composition (R) of the present invention contains substantially no secondary particles. Become. Here, “substantially free of secondary particles” means that the maximum particle size of the secondary particles of the vinyl polymer particles (C) in the resin composition (R) is 3 μm or less. . Moreover, it is more preferable that the secondary particles of the vinyl polymer particles (C) in the resin composition (R) are completely crushed into primary particles. The maximum particle diameter of the secondary particles of the vinyl polymer particles (C) in the resin composition (R) is, for example, the fracture surface of the cured resin plate of the resin composition (R), SEM (JEOL Ltd. ), Product name: “JSM-6300”), and means the diameter of secondary particles when observed at a magnification of 200 times. Thus, when secondary particles are observed at 200 times, normally, secondary particles having a diameter of 3 μm or less cannot be confirmed as particles. That is, the maximum particle diameter of the secondary particles of the vinyl polymer particles (C) in the present invention refers to a situation where the particles cannot be recognized on the observation surface when the particles are observed 200 times using SEM.

  In the present specification, the “secondary particle diameter” refers to a line drawn from one circumferential point through the center point of the circle to the opposite circumference when the secondary particle is a true sphere. It means the length of minutes. In addition, when the particle has a shape other than a true spherical shape, it indicates the length of the longest line segment among the line segments passing through the center point of the circle.

  In addition, the cured resin plate for SEM observation has a thickness of 2 mm by adding a curing agent that can be cured at room temperature to a mixture of the crushed vinyl polymer particles (C) and the epoxy resin (A), and controlling the thickness with a spacer. It can produce.

  In the present invention, core-shell particles having an average primary particle diameter of 0.5 μm or more and 1.0 μm or less are selected as the vinyl polymer particles (C), and the vinyl polymer in the resin composition (R) is selected. When the prepreg is produced by crushing so that the maximum particle diameter of the secondary particles of the particles (C) is 3 μm or less, the vinyl polymer particles (C) are separated from the reinforcing fiber base material by filtration. Impregnation without localized on the substrate surface. Thereby, it becomes possible to manufacture the molded object which is excellent in 90 degree bending strength using said prepreg.

  From the above description, those skilled in the art can easily obtain the vinyl polymer particles (C). That is, those skilled in the art can determine the volume average primary particle diameter, Tg, SP value, and the like based on the above description and by referring to International Publication No. 2010/090246 and International Publication No. 2013/077293. By adjusting, it is possible to easily obtain vinyl polymer particles (C) having an instantaneous maximum thickening value and a thickening start temperature within the above-mentioned ranges.

The content of the vinyl polymer particles (C) in the resin composition (R) is 2 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A). Is preferably 5 parts by weight or more and 15 parts by weight or less.
If content of the vinyl polymer particle (C) in a resin composition (R) is 2 mass parts or more, the inhibitory effect of the resin flow amount at the time of press molding can fully be exhibited. Moreover, if said content is 30 mass parts or less, the fall of the mechanical property of the press molding manufactured from the prepreg in which the resin composition (R) was used is suppressed, and the molding which is excellent in 90 degree bending strength is obtained. can get.

[Optional ingredients]
The resin composition (R) of the present invention may contain any component other than those described above as long as the effects of the present invention are not impaired. Examples of the optional components include thermoplastic elastomers, elastomer fine particles other than vinyl polymer particles (C), core-shell type elastomer fine particles, diluents, inorganic particles such as silica, carbonaceous components such as carbon nanotubes, phosphorus compounds, and the like. Flame retardants, defoaming agents and the like. These may be used alone or in combination of two or more.

[Viscosity of Resin Composition (R)]
The resin composition (R) of the present invention has a viscosity at 30 ° C. of 3.0 × 10 ¹ Pa · s or more and 1.0 × 10 ⁴ Pa · s or less, and 4.0 × 10 ¹ Pa · s or more and 5 or more. 0.0 × 10 ³ Pa · s or less is more preferable, and 5.0 × 10 ¹ Pa · s or more and 3.0 × 10 ³ Pa · s or less is more preferable.
When the viscosity at 30 ° C. of the resin composition (R) is 3.0 × 10 ¹ Pa · s or more, a prepreg having good shape retention can be obtained. Moreover, even if the viscosity increases due to swelling of the vinyl polymer particles (C), a prepreg that can be easily subjected to operations such as molding is obtained. Further, if the viscosity is 1.0 × 10 ⁴ Pa · s or less, the resin composition (R) is easily impregnated into the reinforcing fiber base when the prepreg is produced as described later, and excessive heating is performed. Is preferable because it is not necessary. Moreover, since the drape property of the obtained prepreg is not impaired, it is preferable.
In addition, the “viscosity at 30 ° C.” of the resin composition (R) of the present invention refers to a viscosity at 30 ° C. measured at a temperature rise of 2 ° C./min using a rheometer device. Further, the viscosity is measured immediately after the resin composition (R) is prepared and then cooled to room temperature, or when not measured immediately, it is stored in a freezer at -20 ° C. within 2 weeks. Viscosity.

<Method for Producing Resin Composition (R)>
The resin composition (R) of the present invention can be produced by a conventionally used general method as long as each component is kneaded and uniformly dispersed or dissolved.

  For example, it may be a method in which the respective components constituting the resin composition (R) are mixed at the same time, or as described above, the epoxy resin (A) is preliminarily added to the curing agent (B ), Vinyl polymer particles (C), and other additives may be prepared as appropriate, and the remaining components may be mixed in the master batch. In particular, in order to uniformly disperse the vinyl polymer particles (C) in the epoxy resin (A), a master batch in which the vinyl polymer particles (C) are dispersed in the epoxy resin (A) at a high concentration is prepared. A method of adding the remaining components in the master batch is preferred. In addition, the compounding ratio (mass ratio / vinyl polymer particles (C): epoxy resin (A)) of the vinyl polymer particles (C) and the epoxy resin (A) in the master batch is 5: 5 to 5:40. preferable.

That is, the method for producing the resin composition (R) of the present invention can be a method including the following steps (I) to (III).
Step (I): A part of the epoxy resin (A) having a viscosity at 30 ° C. of 1.0 × 10 ² Pa · s or more and 1.0 × 10 ⁴ Pa · s or less is divided into acrylic resin A vinyl polymer particle (C), which is a core-shell particle having a core layer and a shell layer, is mixed to obtain a mixture (X).
Step (II): The secondary particles of the vinyl polymer particles (C) contained in the mixture (X) are crushed.
Step (III): In the mixture (X), the remainder of the epoxy resin (A) and the curing agent (B) are added and mixed.

  In the step (III), the curing agent (B) added to the mixture (X) is a mixture (H) (curing agent master) obtained by mixing the curing agent (B) with a part of the epoxy resin (A). Batch (H)) is preferred.

  Further, when the temperature of the resin composition (R) increases due to shearing heat generation due to kneading, the resin composition (R) is mixed during kneading, for example, by adjusting the kneading speed or cooling the kneading kettle with water. It is preferable to devise the temperature so as not to increase. That is, in the method for producing the resin composition (R) of the present invention, the mixing temperature in the step (I) or the step (III) is preferably 15 to 80 ° C, and more preferably 20 to 70 ° C.

  Examples of the kneading apparatus used in the present invention include a raking machine, an attritor, a planetary mixer, a dissolver, a triple roll, a kneader, a universal stirrer, a homogenizer, a homodispenser, a ball mill, and a bead mill. Moreover, these kneading apparatuses may be used individually by 1 type, and may be used in combination of 2 or more type.

<Prepreg>
The prepreg of the present invention is composed of the above-described resin composition (R) of the present invention and a reinforcing fiber base. The volume content of the reinforcing fiber base in the prepreg is usually 30% by volume to 80% by volume, and preferably 40% by volume to 70% by volume. By setting the volume content to the lower limit value or more, the mechanical properties of the molded body are likely to be high, and a molded body having excellent 90 ° bending strength can be easily obtained. Moreover, it is preferable to set it to the above upper limit value or less because the reinforcing fiber substrate can be easily impregnated with the resin composition (R) at the time of preparing the prepreg.

  Since the prepreg of the present invention contains the above-described resin composition (R) of the present invention, the amount of resin flow during molding can be easily controlled. Especially, the case where the amount of resin flows when producing a flat press-molded body by press molding with a surface pressure of 8 MPa, a mold temperature of 140 ° C., and a molding time of 5 minutes is more preferably 4.5% by mass or less. Specifically, the prepreg of the present invention is a unidirectional prepreg, and the resin flow amount measured by the following method is preferably 4.5% by mass or less.

First, a prepreg having a fiber content of 240 g / m ^{2 to} 290 g / m ² and a resin content of 28.0% to 32.0% by weight is 298 mm (parallel to the fiber) × 298 mm (fiber And a perpendicular direction)), and then a prepreg laminate in which the fiber directions are aligned and 5 ply is laminated, and its mass is M0. When the surface pressure applied to the prepreg laminate is 8 MPa, the mold temperature is 140 ° C. and the molding time is 5 minutes, and the mass of the flat plate molded body excluding burrs is M1, the following formula The value calculated by (2), that is, the resin flow amount (mass%) is preferably 4.5 mass% or less.
Resin flow rate (mass%) = [(M0−M1) / M0] × 100 (2)

  By setting the resin flow amount to 4.5% by mass or less, it is easy to obtain a smooth molded body having no irregularities on the surface. In addition, it is preferable from the viewpoint of productivity because it requires less labor to remove the flowed resin.

  Moreover, it is preferable that the minimum of the resin flow amount is 1.0 mass% or more. By setting the lower limit of the resin flow amount to 1.0% by mass or more, the resin composition (R) can be easily filled to every corner in the mold. That is, when the resin flow amount of the prepreg is 1.0% by mass or more and 4.5% by mass or less, the flow of the resin composition (R) and the reinforcing fiber base in the prepreg in the molding process can be easily suppressed. It becomes possible to obtain a molded body having an excellent appearance more easily.

(Reinforced fiber substrate)
Various reinforcing fiber base materials in the prepreg of the present invention can be used depending on the purpose of use of the obtained molded body. Specific examples of the reinforcing fiber base include those made of carbon fiber, graphite fiber, aramid fiber, silicon carbide fiber, alumina fiber, boron fiber, tungsten carbide fiber, glass fiber, and the like. These may be used alone or in combination of two or more. Among these, carbon fiber and graphite fiber are preferable in terms of excellent specific strength and specific elastic modulus.
Further, as the carbon fiber or graphite fiber, high strength carbon fiber having a tensile elongation of 1.5% or more is preferable because the strength of the obtained molded body is easily exhibited.

  The form of the reinforcing fiber substrate used in the present invention is, for example, a form in which continuous fibers are aligned in one direction, a form in which continuous fibers are used as a woven fabric, a form in which tows are aligned in one direction and are held by weft auxiliary yarns Examples include a form in which a plurality of sheets of unidirectional reinforcing fibers are stacked in different directions and fastened with auxiliary yarns to form a multiaxial warp knit, or a nonwoven fabric. Among these, from the viewpoint of ease of manufacturing a prepreg, a continuous fiber is aligned in one direction, a continuous fiber is used as a woven fabric, and a tow is aligned in one direction and held by a weft auxiliary yarn. Or a multiaxial warp knit in which a plurality of unidirectional reinforcing fiber sheets are stacked in different directions and fastened with auxiliary yarns. Moreover, in the point of strength expression of the molded object to be obtained, a form in which continuous fibers are aligned in one direction is more preferable.

The basis weight of the reinforcing fiber base can be freely set according to the purpose of use of the molded article to be obtained, but 50 g / m ² or more and 2000 g / m ² or less is a practically preferable range. In order to impregnate the resin composition (R) to obtain a good prepreg, more preferably the basis weight of the reinforcing fiber substrate is 50 g / ^{m 2} or more 600 g / ^{m 2} or less, 50 g / ^{m 2} or more 300g / M ² or less is more preferable.

(Manufacturing method of prepreg)
The prepreg according to the present invention can be produced by a known method. For example, by applying a predetermined amount of the resin composition (R) of the present invention on the surface of a process release material such as release paper, supplying a reinforcing fiber substrate to the surface, and passing the pressing roll, etc. A method of impregnating the reinforcing fiber substrate with the resin composition (R), or directly applying a predetermined amount of the resin composition (R) to the reinforcing fiber substrate, and then removing the reinforcing fiber substrate as necessary It can be produced by a method of impregnating the reinforcing fiber base material with the resin composition (R) by means such as sandwiching between the materials and passing the pressing roll.

(Prepreg laminate)
In general, when a prepreg is press-molded, a prepreg laminate formed by laminating a plurality of prepregs is used. The number of prepregs laminated can be appropriately set according to the use of the molded body obtained by curing the prepreg laminate to be produced.

<Molded body>
The molded body according to the present invention can be obtained by press molding (heating and pressing treatment) the above-described prepreg or prepreg laminate of the present invention.

(Molded body manufacturing method)
The mold used for the press molding of the prepreg is not particularly limited as long as it is a mold that can cure the prepreg of the present invention under high temperature and high pressure. When the mold is closed, the inside of the mold is hermetically sealed. It is preferable to use one having a structure that can be kept at a low level. In addition, “airtight” described in the present specification means that a resin composition constituting the molding material is molded into the mold when a sufficient amount of the molding material to fill the mold is placed in the mold and pressed. It means a state that does not substantially leak from

  Examples of molds that can keep the interior airtight include molds that employ a shear edge structure or a rubber seal structure where the upper mold and lower mold (male mold and female mold) come into contact when the mold is tightened. . In addition, any known mold may be used as long as the inside of the mold can be kept airtight.

  Here, the temperature at the time of press molding the molded body is preferably 100 to 200 ° C, more preferably 120 to 180 ° C. Moreover, 1.0-15.0 MPa is preferable and the pressure at the time of press molding has more preferable 2.0-10.0 MPa. By heating and pressurizing the prepreg of the present invention under such conditions, a molded product having excellent 90 ° bending strength of the present invention can be easily obtained.

  In addition, it is difficult to specify in detail about the state of the molded resin composition in the molded body obtained by curing the prepreg of the present invention by heating and pressing. . In other words, the molded article of the present invention has a situation (impossible / unpractical situation) that it is impossible to specify directly by its structure or characteristics, or is not practical.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated in detail, this invention is not limited by the following description.

<Raw materials>
In this example, the raw materials used for preparing the resin composition (R) and the prepreg are as follows.

[Epoxy resin (A)]
(A-1): “jER828” (product name, manufactured by Mitsubishi Chemical Corporation, bisphenol A type liquid epoxy resin (epoxy equivalent: epoxy equivalent 189 g / eq., Mass average molecular weight: 370)).
(A-2): “jER1002” (product name, manufactured by Mitsubishi Chemical Corporation, bisphenol A type solid epoxy resin (epoxy equivalent: 650 g / eq., Mass average molecular weight: 3200)).
(A-3): “modified epoxy resin” (bisphenol A type epoxy resin (epoxy equivalent 189 g / eq, manufactured by Mitsubishi Chemical Corporation, trade name: jER828) and 4,4′-diaminodiphenyl sulfone (Wakayama Seika) Obtained by mixing at room temperature with a mass ratio of jER828 / 4,4′-diaminodiphenylsulfone = 100/9 and then heating at 150 ° C. A reaction product, a mixture mainly composed of a reaction product of an epoxy resin and an amine compound having at least one sulfur atom in the molecule, an epoxy equivalent of 266 g / eq., And a mass average molecular weight: 2380).
(A-4): “N775” (product name: DIC Corporation, phenol novolac type epoxy resin) (epoxy equivalent: 189 g / eq., Mass average molecular weight: 480)).
(A-5): “jER604” (product name: manufactured by Mitsubishi Chemical Corporation, aminophenol methane type epoxy resin (epoxy equivalent: 120 g / eq., Mass average molecular weight: 480)).

[Curing agent (B)]
(B-1): “Dicyanex (registered trademark) 1400F” (product name: manufactured by Air Products, Inc., dicyandiamide).
(B-2): “2MZA-PW” (product name, manufactured by Shikoku Chemicals Co., Ltd., 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine) .
(B-3): “Omicure 24” (product name, manufactured by PTI Japan, 1,1 ′-(4-methyl-1,3-phenylene) bis (3,3-dimethylurea).
(B-4): “jER Cure (registered trademark) U” (product name: manufactured by Mitsubishi Chemical Corporation, (aliphatic polyamine)).

[Vinyl polymer particles (C)]
(C-1): Vinyl polymer particles prepared in Production Example 1 described later (average particle diameter of primary particles: 0.7 μm).
(C-2): Vinyl polymer particles prepared in Production Example 2 described later (average particle diameter of primary particles: 0.7 μm).
(C-3): Vinyl polymer particles prepared in Production Example 3 described later (average particle diameter of primary particles: 0.7 μm).
(C′-1): “MP1000” (product name, manufactured by Soken Chemical Co., Ltd., acrylic core-shell type fine particles) (average particle diameter of primary particles: 0.3 μm).

Hereinafter, the raw material used for manufacture of vinyl polymer particle | grains (C-1)-(C-3) is shown.
MMA: Methyl methacrylate manufactured by Mitsubishi Rayon Co., Ltd.
-MAA: Mitsubishi Rayon Co., Ltd., methacrylic acid.
N-BMA: Mitsubishi Rayon Co., Ltd., n-butyl methacrylate.
T-BMA: Mitsubishi Rayon Co., Ltd., t-butyl methacrylate.
2-HEMA: Mitsubishi Rayon Co., Ltd., 2-hydroxyethyl methacrylate.
GMA: Mitsubishi Rayon Co., Ltd. glycidyl methacrylate.
-Potassium persulfate: Sigma Aldrich Japan Co., Ltd. reagent special grade.
"Perex OT-P": product name, manufactured by Kao Corporation, sodium dialkylsulfosuccinate
"Perex SS-L": product name, manufactured by Kao Corporation, sodium alkyldiphenyl ether disulfonate.
AIBN: 2,2′-azobisisobutyronitrile manufactured by Otsuka Chemical Co., Ltd.
"Emulgen 106": product name, manufactured by Kao Corporation, polyoxyethylene lauryl ether.

[Reinforced fiber substrate]
Carbon fiber bundle: “TRW4050L” (product name, manufactured by Mitsubishi Rayon Co., Ltd.) (tensile strength 4.1 GPa, tensile elastic modulus 240 GPa, number of filaments 50000, basis weight 3.75 g / m).

<Production Example 1: Preparation of vinyl polymer particles (C-1)>
I put 584g of ion-exchanged water into a 2 liter four-necked flask equipped with a thermometer, nitrogen gas inlet tube, stirring rod, dropping funnel, and cooling tube, thoroughly aerated with nitrogen gas for 30 minutes, and dissolved in ion-exchanged water. Oxygen was replaced. After stopping the aeration of nitrogen gas, the temperature was raised to 80 ° C. while stirring at 200 rpm. When the internal temperature reached 80 ° C., MMA 26.1 g, n-BMA 19.9 g, potassium persulfate 0.4 g as an initiator, and ion-exchanged water 19.6 g (vinyl monomer mixture (c1-1)) Was added and polymerization was carried out for 1 hour.
MMA 205.5g, n-BMA 194.5g, Perex OT-P3.6g, and ion-exchanged water 200g previously mixed (vinyl monomer mixture (c1-2)) were added dropwise thereto.

  Thereafter, after no heat generation due to polymerization of the vinyl monomer mixture (c1-1) and the vinyl monomer mixture (c1-2) was observed, the vinyl monomer mixture was held for 1 hour and mixed in advance. (C1-3) (a mixture of MMA 382.7 g, MAA 17.3 g, Perex OT-P 4.0 g, Emulgen 106 4.0 g, and ion-exchanged water 200 g) was added. After the addition, stirring was continued at 80 ° C. for 1 hour to obtain a vinyl polymer particle dispersion (CL1).

The vinyl polymer particle dispersion liquid (CL1) is spray-dried using an L-8 type spray dryer (manufactured by Okawara Chemical Co., Ltd.) (inlet temperature / outlet temperature = 150/65 ° C., disk rotation) Several 25,000 rpm) and vinyl polymer particles (C-1) were obtained. The average particle diameter of the primary particle diameter of the obtained vinyl polymer particles (C-1) was 0.7 μm.
In the vinyl polymer particles (C-1), the shell layer (the outermost emulsion polymer layer (i)) is a layer formed by polymerization of the vinyl monomer mixture (c1-3). Moreover, the part formed by polymerizing the vinyl monomer mixture (c1-1) and the vinyl monomer mixture (c1-2) corresponds to the core layer (the other emulsion polymer layer (ii)). The mass ratio of the shell layer to the core layer (shell layer: core layer ((i) layer: (ii) layer)) in the vinyl polymer particles (C-1) was 50:50. The Tg of the shell layer was 109.1 ° C., and the SP value was 20.58 [(J / cm ³ ) ^1/2 ].

<Production Example 2: Preparation of vinyl polymer particles (C-2)>
Add 544 g of ion-exchanged water to a 2 liter four-necked flask equipped with a thermometer, nitrogen gas inlet tube, stirring rod, dropping funnel, and cooling tube, thoroughly vent nitrogen gas for 30 minutes, and dissolve in ion-exchanged water. Oxygen was replaced. After stopping the aeration of nitrogen gas, the temperature was raised to 80 ° C. while stirring at 200 rpm. When the internal temperature reached 80 ° C., 26.1 g of MMA, 19.9 g of n-BMA, 0.4 g of potassium persulfate and 16.0 g of ion-exchanged water (vinyl monomer mixture (c2-1) were added as initiators) Polymerization was performed for 1 hour.

  Here, MMA 334.1 g, t-BMA 316.1 g, 2-HEMA 21.7 g, Perex OT-P 6.1 g, and ion-exchanged water 251.2 g were previously mixed (vinyl monomer mixture (c2-2)). ) Was added dropwise.

  Thereafter, after no heat generation due to polymerization of the vinyl monomer mixture (c2-1) and the vinyl monomer mixture (c2-2) was observed, the mixture was kept for 1 hour and mixed in advance. c2-3) (MMA 77.0 g, 2-HEMA 3.0 g, Perex OT-P 0.8 g, and ion-exchanged water 28 g) was added. After the addition, stirring was continued at 80 ° C. for 1 hour to obtain a vinyl polymer particle dispersion (CL2).

Then, the vinyl polymer particle dispersion (CL2) is spray-dried using an L-8 type spray dryer (manufactured by Okawara Chemical Co., Ltd.) (inlet temperature / outlet temperature = 150/65 ° C., disk rotational speed 25000 rpm). Vinyl polymer particles (C-2) were obtained. The average particle diameter of the primary particles of the obtained vinyl polymer particles (C-2) was 0.7 μm.
In the vinyl polymer particles (C-2), the shell layer (the outermost emulsion polymer layer (i)) is a layer formed by polymerization of the vinyl monomer mixture (c2-3). Moreover, the part formed by polymerizing the vinyl monomer mixture (c2-1) and the vinyl monomer mixture (c2-2) corresponds to the core layer (other emulsion polymer layer (ii)). The mass ratio of the shell layer to the core layer (shell layer: core layer ((i) layer: (ii) layer)) in the vinyl polymer particles (C-2) was 10:90. The Tg of the shell layer was 102 ° C., and the SP value was 20.53 [(J / cm ³ ) ^1/2 ].

<Production Example 3: Preparation of vinyl polymer particles (C-3)>
Add 544 g of ion-exchanged water to a 2 liter four-necked flask equipped with a thermometer, nitrogen gas inlet tube, stirring rod, dropping funnel, and cooling tube, thoroughly vent nitrogen gas for 30 minutes, and dissolve in ion-exchanged water. Oxygen was replaced. After stopping the aeration of nitrogen gas, the temperature was raised to 80 ° C. while stirring at 200 rpm. When the internal temperature reaches 80 ° C., 26.1 g of MMA, 19.9 g of n-BMA, 0.16 g of potassium persulfate and 20.0 g of ion-exchanged water (vinyl monomer mixture (c3-1)) are added as an initiator. Then, polymerization was carried out for 1 hour.

  Here, 317.4 g of MMA, 242.6 g of n-BMA, 4.0 g of GMA, 4.0 g of Perex OT-P, 1.6 g of Emulgen 106, 0.24 g of AIBN and 280.0 g of ion-exchanged water are mixed beforehand (single vinyl) A monomer mixture (c3-2)) and a mixture obtained by adding 1.6 g of potassium persulfate and 40.0 g of ion-exchanged water as an initiator were added dropwise.

  Thereafter, after the generation of heat due to the polymerization of the vinyl monomer mixture (c3-1) and the vinyl monomer mixture (c3-2) is no longer observed, the vinyl monomer mixture is kept for one hour and mixed in advance. (C3-3) (MMA 219.1 g, MAA 20.9 g, OTG 0.9 g, Perex OT-P 2.4 g, 2.4 g of Emulgen 106, and 120 g of ion-exchanged water) was added. After the addition, polymerization was carried out by continuing stirring at 80 ° C. for 1 hour.

  Thereafter, the vinyl monomer mixture (c3-1), the vinyl monomer mixture (c3-2), and the vinyl monomer mixture (c3-3) no longer generate heat due to polymerization. The mixture (c3-4) (MAA 3.1 g, ion-exchanged water 62.5 g) was added. After the addition, stirring was continued at 80 ° C. for 1 hour to obtain a vinyl polymer particle dispersion (CL3).

Then, the vinyl polymer particle dispersion (CL3) is spray-dried using an L-8 type spray dryer (manufactured by Okawara Chemical Co., Ltd.) (inlet temperature / outlet temperature = 150/65 ° C., disk rotational speed 25000 rpm). And vinyl polymer particles (C-3) were obtained. The average particle diameter of the primary particles of the obtained vinyl polymer particles (C-3) was 0.7 μm.
In the vinyl polymer particles (C-3), the shell layer (the outermost emulsion polymer layer (i)) is composed of the vinyl monomer mixture (c3-3) and the vinyl monomer mixture (c3-4). It is a layer formed by polymerization. Moreover, the part formed by polymerizing each of the vinyl monomer mixture (c3-1) and the vinyl monomer mixture (c3-2) corresponds to the core layer (other emulsion polymer layer (ii)). The mass ratio of the shell layer and the core layer (shell layer: core layer ((i) layer: (ii) layer)) in the vinyl polymer particles (C-3) was 30:70. The Tg of the shell layer was 114.4 ° C., and the SP value was 20.92 [(J / cm ³ ) ^1/2 ].

<Production Example 4: Preparation of curing agent master batch (H-1)>
Curing agent (B-1) (Dicyanex 1400F), curing agent (B-2) (Omicure 24), curing agent (B-3) (2MZA-PW), and epoxy resin (A-1) (jER828) The mixture was weighed into a container so as to have a mass ratio of 6: 6: 2: 15, and stirred and mixed. This was further finely mixed with a three-roll mill to obtain a curing agent master batch (H-1).

<Production Example 5: Preparation of curing agent master batch (H-2)>
Curing agent (B-1) (Dicyanex 1400F), curing agent (B-2) (Omicure 24), curing agent (B-3) (2MZA-PW), and epoxy resin (A-1) (jER828) The mixture was weighed in a container so as to have a mass ratio of 6: 4: 2: 15, and stirred and mixed. This was further finely mixed with a three-roll mill to obtain a curing agent master batch (H-2).

  Table 1 below shows the compositions of the curing agent master batches (H-1) and (H-2).

<Production Example 6: Preparation of vinyl polymer particle master batch (X-1)>
A container of epoxy resin (A-4) (N775) and epoxy resin (A-1) (jER828) and vinyl polymer particles (C-1) in a mass ratio of 5:10:10. Weighed and stirred and mixed. This was further finely mixed with a three-roll mill, and then the vinyl polymer particles were crushed to obtain a vinyl polymer particle master batch (X-1).

<Production Example 7: Preparation of vinyl polymer particle master batch (X-2)>
The epoxy resin (A-1) and the vinyl polymer particles (C-1) were weighed in a container so as to have a mass ratio of 15:10, and stirred and mixed. This was further finely mixed with a three-roll mill, and then the vinyl polymer particles were crushed to obtain a vinyl polymer particle master batch (X-2).

<Production Example 8: Preparation of vinyl polymer particle master batch (X-3)>
The epoxy resin (A-4) and the epoxy resin (A-1) and the vinyl polymer particles (C-2) are weighed in a container so that the mass ratio is 5:10:10. Mixed. This was further finely mixed with a three-roll mill, and then the vinyl polymer particles were pulverized to obtain a vinyl polymer particle master batch (X-3).

<Production Example 9: Preparation of vinyl polymer particle master batch (X-4)>
The epoxy resin (A-4) and the epoxy resin (A-1) and the vinyl polymer particles (C-3) are weighed in a container so as to be a mass ratio of 5:10:10, and stirred. Mixed. This was further finely mixed with a three-roll mill, and then the vinyl polymer particles were crushed to obtain a vinyl polymer particle master batch (X-4).

<Production Example 10: Preparation of vinyl polymer particle master batch (X-5)>
The epoxy resin (A-2) (jER1002) and the epoxy resin (A-1) and the vinyl polymer particles (C-1) are weighed in a container so that the mass ratio is 5:10:10. , Stirred and mixed. This was further finely mixed with a three-roll mill, and then the vinyl polymer particles were pulverized to obtain a vinyl polymer particle master batch (X-5).

<Production Example 11: Preparation of vinyl polymer particle master batch (X'-1)>
The epoxy resin (A-4) and the epoxy resin (A-1) and the vinyl polymer particles (C′-1) are weighed in a container so as to be a mass ratio of 5:10:10 and stirred.・ Mixed. This was further finely mixed with a three-roll mill, and then the vinyl polymer particles were crushed to obtain a vinyl polymer particle master batch (X′-1).

  Table 2 below shows a list of compositions of the vinyl polymer particle master batches (X-1) to (X-5) and (X′-1).

<Measurement and evaluation method>
[Average particle diameter of primary particles of vinyl polymer particles (C)]
The emulsion of vinyl polymer particles (C) is diluted with ion-exchanged water, and a volume average primary is used as the emulsion particle diameter using a laser diffraction scattering type particle size distribution analyzer (product name: LA-910W, manufactured by Horiba, Ltd.). The particle size was measured.

[How to obtain Tg of shell layer and core layer of vinyl polymer particle (C)]
Tg is a value obtained from the following FOX equation (hereinafter, equation (3)). Specifically, when the polymer is a homopolymer, it is a copolymer of n types of monomers using standard analytical values described in the “Polymer Data Handbook” edited by the Society of Polymer Science. In the case, it was calculated from Tg of each monomer. The literature values of Tg of typical homopolymers are shown in Table 3 below. The abbreviations in Table 3 below are the same as those described for the raw materials used for the vinyl polymer particles (C) described above.

[How to Obtain SP Values for Shell Layer and Core Layer of Vinyl Polymer Particle (C)]
The SP value was determined by substituting the monomer SP value (SP (Ui)) of the repeating unit in the polymer constituting the shell layer and the core layer into the above formula (1). SP (Ui) is described in Polymer Engineering and Science, Vol. 14, 147 (1974). In Table 3, the SP values (SP (Ui)) of typical monomers are shown (however, the values described in JP 2000-1633 A were adopted for the SP values of GMA). ).

[Measurement of viscosity of resin composition (R)]
The viscosity at 30 ° C. and the minimum viscosity of the resin compositions (R) obtained in the respective examples and comparative examples were measured under the following measurement conditions.
Apparatus: Rheometer (manufactured by Thermo Fisher Scientific Co., Ltd., product name: “HAAKE MARS 40 TM-EL-H”)
Measurement mode: constant stress, stress value 300Pa
Frequency: 10 rad / sec Plate diameter: 25 mm
Plate type: Parallel plate Plate gap: 0.5mm
Plate temperature at the start of measurement: 30 ° C
Temperature increase rate: 2 ° C / min

<Crushing treatment of vinyl polymer particles (C)>
In this example, in evaluating the crushing treatment of the secondary particles, first, regarding the vinyl polymer particle master batches (X-1) to (X-5) and (X′-1), three A roll (manufactured by Inoue Seisakusho Co., Ltd.) was passed under the following conditions to crush the secondary particles of the vinyl polymer particles (C).

(Three rolls)
Roll diameter 120mm
Roll speed 1st roll (input side) 25rpm
Second roll 60rpm
Third roll (discharge side) 170rpm
Clearance between rolls 8-10μm

[Observation of secondary particle crushing treatment of vinyl polymer particles (C)]
The fracture surface of the cured resin plate prepared by the following procedure was observed at a magnification of 200 times using SEM (manufactured by JEOL Ltd., product name: “JSM-6300”). When secondary particles can be confirmed at this magnification, the diameter (particle diameter) of the secondary particles is measured, and when secondary particles cannot be confirmed, all secondary particles can be broken into primary particles. It was judged that When the average particle diameter of the secondary particles is 3 μm or less, the secondary particles cannot be confirmed at the above magnification. Therefore, when particles cannot be confirmed when observed at 200 times, that is, when the diameter of the secondary particles is 3 μm or less, the particles are crushed or the secondary particles are very small and substantially present. Judged to be in a state not to do.

(Method for creating cured resin plate)
65 parts by mass of epoxy resin (A-1) and 20 parts by mass of curing agent (B-4) are added to 25 parts by mass of the vinyl polymer particle master batch crushed by the above method, and a resin plate having a thickness of 2 mm. Was made. Thereafter, the resin plate was left still for 15 hours to obtain a cured resin plate.

<Press molding>
The unidirectional prepreg obtained in each Example and Comparative Example was cut into a size of 298 mm (parallel to the fiber) x 298 mm (perpendicular to the fiber), and 10 ply laminated with the fiber direction aligned, and the prepreg laminate did. Then, the surface pressure applied to the prepreg laminate was 4 MPa, the mold temperature was 140 ° C., press molding was performed for 5 minutes, and burrs were removed to obtain a flat molded body.

[90 ° bending test]
The molded body obtained above was cut with a wet diamond cutter into a size of 63 mm in length (perpendicular to the fiber) × width (perpendicular to the fiber) 12.7 mm to prepare a test piece. About this test piece, using a universal testing machine (product name: Instron 4465, analysis software: Bluehill, manufactured by Instron Co.), indenter R: 5.0, L / D: 16, crosshead speed: according to ASTM D790 A three-point bending test was performed under conditions of 0.78 to 0.96 mm / min, and a 90 ° bending strength was calculated.

<Reference Example 1>
15 parts by mass of epoxy resin (A-1) (jER828) and 10 parts by mass of vinyl polymer particles (C-1) were weighed and "Mazerustar KK250s" (product name, manufactured by Kurashiki Boseki Co., Ltd.) at room temperature. The mixture was stirred and mixed. The resulting mixture was then placed on a three roll. Further, 65 parts by mass of epoxy resin (A-1) and 20 parts by mass of curing agent (B-4) (jER cure U) were added to prepare a resin plate having a thickness of 2 mmt. Then, it was left still for 15 hours to obtain a cured resin plate.
And the SEM observation of the torn surface of a cured resin board was performed, and the presence or absence of the secondary particle was observed. The results are shown in Table 4 below.

<Reference Example 2>
12 parts by mass of the epoxy resin (A-1), 3 parts by mass of the epoxy resin (A-4) (N775), and 10 parts by mass of the vinyl polymer particles (C-1) were weighed. (Product name, Kurashiki Boseki Co., Ltd.). The resulting mixture was then placed on a three roll. Further, 65 parts by mass of epoxy resin (A-1) and 20 parts by mass of curing agent (B-4) were added to prepare a resin plate having a thickness of 2 mmt. Then, it was left still for 15 hours to obtain a cured resin plate.
And the SEM observation of the torn surface of a cured resin board was performed, and the presence or absence of the secondary particle was observed. The results are shown in Table 4 below.

<Reference Example 3>
10 parts by mass of epoxy resin (A-1), 5 parts by mass of epoxy resin (A-4), and 10 parts by mass of vinyl polymer particles (C-1) are weighed and "Mazerustar KK250s" (product) Name, Kurashiki Boseki Co., Ltd.). The resulting mixture was then placed on a three roll. Further, 65 parts by mass of epoxy resin (A-1) and 20 parts by mass of curing agent (B-4) were added to prepare a resin plate having a thickness of 2 mmt. Then, it was left still for 15 hours to obtain a cured resin plate.
And the SEM observation of the torn surface of a cured resin board was performed, and the presence or absence of the secondary particle was observed. The results are shown in Table 4 below.

<Reference Example 4>
8 parts by mass of epoxy resin (A-1), 7 parts by mass of epoxy resin (A-4) and 10 parts by mass of vinyl polymer particles (C-1) are weighed, and "Mazerustar KK250s" (product) Name, Kurashiki Boseki Co., Ltd.). The resulting mixture was then placed on a three roll. Further, 65 parts by mass of epoxy resin (A-1) and 20 parts by mass of curing agent (B-4) were added to prepare a resin plate having a thickness of 2 mmt. Then, it was left still for 15 hours to obtain a cured resin plate.
And the SEM observation of the torn surface of a cured resin board was performed, and the presence or absence of the secondary particle was observed. The results are shown in Table 4 below.

<Reference Example 5>
Weigh 5 parts by mass of epoxy resin (A-1), 10 parts by mass of epoxy resin (A-4), and 10 parts by mass of vinyl polymer particles (C-1). Name, Kurashiki Boseki Co., Ltd.). Subsequently, the obtained mixture was applied to a three roll, but the resin could not pass through the three roll. The results are shown in Table 4 below.

From the results shown in Table 4, the viscosity at 30 ° C. of the epoxy resin (A) in which the vinyl polymer particles (C) (core shell particles) are dispersed is 1.0 × 10 ² Pa · s or more and 1.0 × 10 ⁴ Pa. -It turns out that it is preferable that it is s or less. That is, it can be seen that if the viscosity of the epoxy resin (A) at 30 ° C. is within the above range, the secondary particles contained in the vinyl polymer particles (C) can be crushed more effectively.

<Example 1>
45 parts by mass of epoxy resin (A-1) (jER828), 5 parts by mass of epoxy resin (A-3) (modified epoxy resin), and 20 parts by mass of epoxy resin (A-4) (N775) in the melting pot The sample was weighed, and the melting pot was heated to 80 ° C and mixed, and then cooled to about 60 ° C. Subsequently, 29 parts by mass of the previously prepared curing agent masterbatch (H-1) and 25 parts by mass of the vinyl polymer particle masterbatch (X-1) were added to the dissolution vessel, and the mixture was stirred at 60 ° C. 1 was obtained.

When the viscosity of the obtained resin composition 1 was measured, the viscosity in 30 degreeC was 9.6 * 10 < ¹ > Pa * s.

  Moreover, the obtained resin composition 1 was made into a 2 mm-thick resin plate and cured in an oven at 140 ° C. for 40 minutes to obtain a resin plate. And when SEM observation of the fracture surface of the cured resin plate was performed, secondary particles with a particle diameter of more than 3 μm were not confirmed, so all were broken into primary particles, or the secondary particles were very small, Judged to be in a substantially non-existent state.

Furthermore, the obtained resin composition 1 was apply | coated on the release paper at 60 degreeC using the multicoater M-500 type | mold made from Hirano tech seed, and the resin film was obtained.
Next, a unidirectional prepreg 1 was obtained by winding a carbon fiber bundle on the resin-coated surface of the obtained resin film with a drum wind, sandwiching the bundle with the same film, and impregnating the resin composition 1. When the basis weight was measured for the obtained prepreg 1, the fiber content was 247 g / m ² and the resin content was 32.5% (mass%, the same applies hereinafter).
And the obtained prepreg 1 was laminated | stacked and the press-molding was performed and the molded object 1 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 1.

<Example 2>
A resin composition 2 was obtained in the same manner as in Example 1 except that the composition components were as shown in Table 5 below.
When the viscosity of the obtained resin composition 2 was measured, the viscosity in 30 degreeC was 5.9 * 10 < ¹ > Pa * s.

Moreover, the prepreg 2 was obtained similarly to Example 1 using the obtained resin composition 2 and the carbon fiber bundle. When the basis weight was measured for the obtained prepreg 2, the fiber content was 242 g / m ² and the resin content was 32.9%.
And the obtained prepreg 2 was laminated | stacked and press-molded and the molding 2 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 2.

<Example 3>
A resin composition 3 was obtained in the same manner as in Example 1 except that the composition components were as shown in Table 5 below.
When the viscosity of the obtained resin composition 3 was measured, the viscosity in 30 degreeC was 7.6 * 10 < ¹ > Pa * s.

Moreover, the prepreg 3 was obtained similarly to Example 1 using the obtained resin composition 3 and carbon fiber bundle. When the basis weight was measured for the obtained prepreg 3, the fiber content was 247 g / m ² and the resin content was 31.4%.
And the obtained prepreg 3 was laminated | stacked and press-molded and the molded object 3 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 3.

<Example 4>
A resin composition 4 was obtained in the same manner as in Example 1 except that the composition components were changed to the compositions shown in Table 5 below.
When the viscosity of the obtained resin composition 4 was measured, the viscosity in 30 degreeC was 8.0 * 10 < ¹ > Pa * s.

Moreover, the prepreg 4 was obtained similarly to Example 1 using the obtained resin composition 4 and the carbon fiber bundle. When the basis weight was measured for the obtained prepreg 4, the fiber content was 251 g / m ² and the resin content was 31.1%.
And the prepreg 4 was laminated | stacked and press-molded and the molded object 4 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 4.

<Example 5>
A resin composition 5 was obtained in the same manner as in Example 1 except that the composition components were changed to the compositions shown in Table 5 below.
When the viscosity of the obtained resin composition 5 was measured, the viscosity in 30 degreeC was 9.0 * 10 < ¹ > Pa * s.

A prepreg 5 was obtained in the same manner as in Example 1 by using the obtained resin composition 5 and carbon fiber bundle. When the basis weight was measured for the obtained prepreg 5, the fiber content was 259 g / m ² and the resin content was 31.0%.
And the prepreg 5 was laminated | stacked and press-molded and the molding 5 was obtained. The 90 ° bending strength of this molded body 5 is shown in Table 5 below.

<Example 6>
A resin composition 6 was obtained in the same manner as in Example 1 except that the composition components were changed to the compositions shown in Table 5 below.
When the viscosity of the obtained resin composition 6 was measured, the viscosity in 30 degreeC was 7.6 * 10 < ² > Pa * s.

A prepreg 6 was obtained in the same manner as in Example 1 by using the obtained resin composition 6 and carbon fiber bundle. When the basis weight was measured for the obtained prepreg 6, the fiber content was 248 g / m ² and the resin content was 31.8%.
And the prepreg 6 was laminated | stacked and press-molded and the molded object 6 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 6.

<Example 7>
A resin composition 7 was obtained in the same manner as in Example 1 except that the composition components were changed to the compositions shown in Table 5 below.
When the viscosity of the obtained resin composition 7 was measured, the viscosity in 30 degreeC was 2.2 * 10 < ³ > Pa * s.

A prepreg 7 was obtained in the same manner as in Example 1 by using the obtained resin composition 7 and carbon fiber bundle. When the basis weight was measured for the obtained prepreg 7, the fiber content was 251 g / m ² and the resin content was 32.1%.
And the prepreg 7 was laminated | stacked and press-molded and the molded object 7 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 7.

<Comparative Example 1>
A resin composition 8 was obtained in the same manner as in Example 1 except that the composition components were changed to the compositions shown in Table 5 below.
When the viscosity of the obtained resin composition 8 was measured, the viscosity in 30 degreeC was 9.5 * 10 < ¹ > Pa * s.

A prepreg 8 was obtained in the same manner as in Example 1 using the obtained resin composition 8 and carbon fiber bundle. When the basis weight was measured for the obtained prepreg 8, the fiber content was 253 g / m ² and the resin content was 30.1%.
And the prepreg 8 was laminated | stacked and press-molded and the molded object 8 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 8. Here, as shown in Table 4, in the resin composition 8, the 30 ° C. viscosity of the epoxy resin (A) was as low as 8 Pa · s. Therefore, secondary particles having a particle diameter of more than 3 μm remain in the resin composition 8, and the vinyl polymer particles are not sufficiently crushed, or have a small diameter so that the secondary particles are not substantially present. It was not converted. As a result, the bending strength of the molded body 8 was as low as 56 MPa.

<Comparative example 2>
A resin composition 9 was obtained in the same manner as in Example 1 except that the composition components were as shown in Table 5 below.
When the viscosity of the obtained resin composition 9 was measured, the viscosity in 30 degreeC was 2.2 * 10 < ² > Pa * s.

A prepreg 9 was obtained in the same manner as in Example 1 by using the obtained resin composition 9 and carbon fiber bundle. When the basis weight was measured for the obtained prepreg 9, the fiber content was 250 g / m ² and the resin content was 30.6%.
And the prepreg 9 was laminated | stacked and press-molded and the molded object 9 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 9. Here, the resin composition 9 contains 40 parts by mass of vinyl polymer particles (C) in the composition. As a result, although secondary particles were not confirmed in the resin composition 9, the 90 ° bending strength of the molded body 9 was as low as 65 MPa.

<Comparative Example 3>
A resin composition 10 was obtained in the same manner as in Example 1 except that the composition components were changed to the compositions shown in Table 5 below.
When the viscosity of the obtained resin composition 10 was measured, the viscosity in 30 degreeC was 1.7 * 10 < ² > Pa * s.

A prepreg 10 was obtained in the same manner as in Example 1 using the obtained resin composition 10 and carbon fiber bundle. When the basis weight was measured for the obtained prepreg 10, the fiber content was 252 g / m ² and the resin content was 30.5%.
And the prepreg 10 was laminated | stacked and press-molded and the molded object 10 was obtained. Table 5 below shows the 90 ° bending strength of the molded body 10. Here, the resin composition 10 includes vinyl polymer particles having an average primary particle size of 0.3 μm. As a result, although secondary particles were not confirmed in the resin composition 10, the 90 ° bending strength of the molded body 10 was as low as 67 MPa.

  From the results shown in Table 5, in Examples 1 to 7 to which the present invention was applied, molded bodies excellent in 90 ° bending strength were obtained. On the other hand, in Comparative Examples 1 to 3, which are outside the scope of the present invention, the 90 ° bending strength of the obtained molded body was lower than that of the present invention.

  From the results of the examples described above, according to the resin composition of the present invention and the method for producing the same, a prepreg capable of producing a molded article having excellent 90 ° bending strength by substantially not including secondary particles is provided. It became clear that we could do it. Moreover, it has been clarified that the prepreg of the present invention can produce a molded article having excellent 90 ° bending strength. Furthermore, it became clear that the molded object of this invention is excellent in 90 degree bending strength.

Claims (7)

A resin composition (R) comprising an epoxy resin (A), a curing agent (B), and vinyl polymer particles (C),
The vinyl polymer particles (C) are core-shell particles having a core layer and a shell layer made of an acrylic resin,
Content of the said vinyl polymer particle (C) in the said resin composition (R) is 2 mass parts or more and 30 mass parts or less with respect to 100 mass parts of said epoxy resins (A),
The average particle diameter of primary particles of the vinyl polymer particles (C) is 0.5 μm or more and 1.0 μm or less,
The viscosity at 30 ° C. of the resin composition (R) is 3.0 × 10 ¹ Pa · s or more and 5.0 × 10 ³ Pa · s or less,
Resin composition (R) whose maximum particle diameter of the secondary particle of the said vinyl polymer particle (C) in the said resin composition (R) is 3 micrometers or less. In the vinyl polymer particles (C), the glass transition temperature of the shell layer is 85 ° C. or higher and 115 ° C. or lower,
The solubility parameter of the shell layer is 20.00 [(J / cm ³ ) ^1/2 ] or more and 21.50 [(J / cm ³ ) ^1/2 ] or less,
The resin composition (R) according to claim 1, wherein a mass ratio of the shell layer to the core layer (shell layer: core layer) is 50:50 to 10:90.   The vinyl polymer particles (C) are prepared by emulsion polymerization of at least two kinds of vinyl monomer mixtures having different compositions in two or more stages to prepare an emulsion containing the vinyl polymer, and the emulsion containing the vinyl polymer is prepared. The resin composition (R) according to claim 1 or 2, which is particles obtained by spray drying.   At least one vinyl monomer selected from the group consisting of (meth) acrylate and (meth) acrylic acid, each of which is a mixture of at least two or more vinyl monomers having different compositions. The resin composition (R) according to any one of claims 1 to 3, which is a mixture containing a body. A method for producing the resin composition (R) according to any one of claims 1 to 4,
A part of the epoxy resin (A) having a viscosity at 30 ° C. of 1.0 × 10 ² Pa · s or more and 1.0 × 10 ⁴ Pa · s or less is divided into a core layer and a shell made of acrylic resin. Step (I) of mixing vinyl polymer particles (C), which are core-shell particles having a layer, to obtain a mixture (X);
A step (II) of crushing secondary particles of the vinyl polymer particles (C) contained in the mixture (X);
Step (III) of adding and mixing the remainder of the epoxy resin (A) and the curing agent (B) in the mixture (X);
The manufacturing method of the resin composition (R) containing this.   A prepreg comprising the resin composition (R) according to any one of claims 1 to 4 and a reinforcing fiber substrate.   The molded object obtained by heat-pressing and hardening the prepreg of Claim 6.